1. Field of the Invention
This invention relates to a breakaway connection between a detachable arrow shaft insert and an arrow shaft whereby an arrowhead remains secured with respect to the arrow shaft during flight but the arrow shaft is separated from the arrowhead leaving the arrowhead lodged within a target.
2. Description of the Prior Art
Conventional recovery systems for arrows have transmitters which are either housed in the broadhead or arrowhead, or have components which are mounted external to the arrow shaft. Such systems drastically reduce the aerodynamic characteristics of the flight pattern of the arrow. Other conventional systems employ a transmitter housed within the arrow shaft. However, with the transmitter mounted within the arrow shaft, the transmitter is permanently secured within the arrow shaft. Conventional tracking systems do not compensate for removal of the transmitter in a situation where an animal, such as a deer, pulls the arrow shaft to dislodge the arrow from its body. When an animal removes the arrow from its body, which typically occurs when the animal is not immediately killed, the transmitter is removed from the animal and thus defeats the purpose of tracking the injured animal. Thus, it is one object of this invention to design a transmitter that can be housed within an arrow shaft in such a manner that when an animal exerts an outward pulling force on the arrow shaft, the arrow shaft separates from the arrow shaft insert leaving the arrowhead, arrow shaft insert and the transmitting means within the animal's body. With such a tracking system, it is apparent that even if the animal removes the arrow shaft or the arrow shaft catches a tree limb or the like and is removed from the animal's body, the transmitting means will remain lodged in the animal's body.
Conventional arrowheads have threaded shaft portions extending from the rearward end of the arrowhead. The external threads of such shafts engage with the internal threads of an arrow shaft insert or adapter sleeve permanently secured within the arrow shaft, for example with epoxy or another adhesive. Most arrow shaft inserts or adapter sleeves are permanently secured within the arrow shaft, since a primary concern of archers has been to remove the arrowhead when removing an arrow or arrow shaft from a target or animal. An amateur can easily remove a conventional or existing arrow shaft insert by heating the shaft, which melts the adhesive, and pulling the arrow shaft insert outward. In conventional arrowhead connections, the arrow shaft insert is also permanently attached to one end of an arrow shaft by having the arrow shaft and the insert an integral piece. Once the arrow shaft insert is permanently secured with respect to the arrow shaft, an arrowhead is threadedly engaged with the arrow shaft insert.
With respect to arrow tracking devices, one prior design, according to an advertisement in Bowhunting guide '87, Edition No. 215, 1987/88 Season, a "TAG-N-TRAIL" device marketed by flex-fletch products, for detecting the location of an animal, uses a string having one end attached to a harpoon. The harpoon attaches to a holding base mounted on the outer surface of an arrow shaft, near the arrowhead. Apparently, the line trailing from the harpoon has a free end. In such design, when an arrow discharges from the bow, the line end attached to the arrow shaft travels with the arrow and thus pulls the trailing line. The harpoon either lodges within or passes through the animal's body.
Further regarding arrow tracking devices, many problems arise with using a string attached to an arrow shaft for detecting the location of an animal. The length of string will reduce the distance the arrow can travel. Should the arrow hit an animal and cause the animal to run, the line may tangle in the brush and either sever the line or cause the arrow shaft to break. Long lengths of line left in the brush or at the hunting site create tripping hazards for both humans and animals. More importantly, the line attached to the harpoon which is mounted on the arrow shaft will create unnecessary drag forces that misguide the arrow and dramatically reduce the arrow aerodynamics. A harpoon and holding base mounted to the side of an arrow shaft also create an unbalanced arrow shaft which misguides the arrow during flight.
U.S. Pat. No. 4,704,612 discloses a method and apparatus for tracking and recovering a hunting arrow. A transmitter is mounted within an arrow shaft. The arrowhead is mounted in an insert which is fixedly and permanently secured within the arrow shaft. Once the arrow is shot, an inertia-activation switch momentarily closes, causing the transmitter to switch on and transmit a signal.
U.S. Pat. No. 4,544,163 teaches an arrow nock having a cylindrical body with a plug shaft with longitudinal grooves to accept adhesive to ensure that there is an adhesive bond between the interior of the arrow shaft and the nock plug.
U.S. Pat. No. 4,381,866 discloses an arrowhead assembly which includes a compressible, resilient O-ring which fits over the blade carrying body and is adjacent a rearward side of a nondeformable blade locking ring. The opposite side of the O-ring is adjacent the front and external face of an arrow shaft insert. The compressible O-ring is compressed when the arrowhead is assembled and thus uneven forces by the compressible ring are accommodated by canting of the nondeformable blade locking ring thereby providing solid engagement of the mating bevel and the chamfer while tightly holding the removable blades in position. It is noted that in an assembled position, the compressible O-ring is not housed within the cavity of the arrow shaft insert, but rather is external to the arrow shaft insert.
U.S. Pat. No. 4,749,198 discloses a trackable arrow which includes a transmitter mounted within the arrow shaft. The arrowhead is mounted within an insert which is permanently held in place by an interference fit with the inside walls of the arrow shaft. The '198 patent neither teaches nor suggests an intentionally detachable connection between the arrow shaft insert and the arrow shaft, which would enable an animal to remove an arrow shaft from an arrow which is lodged in its body while leaving the arrowhead and arrowhead insert within its body.